Conventional image processing techniques include using two source images nominally of the same scene to produce a single target image of better quality or higher resolution than either of the source images.
In super-resolution, multiple differently exposed lower resolution images can be combined to produce a single higher resolution image of a scene, for example, as disclosed in “High-Resolution Image Reconstruction from Multiple Differently Exposed Images”, Gunturk et al., IEEE Signal Processing Letters, Vol. 13, No. 4, April 2006; or “Optimizing and Learning for Super-resolution”, Lyndsey Pickup et al, BMVC 2006, 4-7 Sep. 2006, Edinburgh, UK. However, in super-resolution, blurring of the individual source images either because of camera or subject motion are usually not of concern before the combination of the source images.
U.S. Pat. No. 7,072,525 discloses adaptive filtering of a target version of an image that has been produced by processing an original version of the image to mitigate the effects of processing including adaptive gain noise, up-sampling artifacts or compression artifacts.
PCT Application No. PCT/EP2005/011011 (Ref: FN109) discloses using information from one or more presumed-sharp short exposure time (SET) preview images to calculate a motion function for a fully exposed higher resolution main image to assist in the de-blurring of the main image.
Indeed many other documents, including US 2006/0187308, Suk Hwan Lim et al.; and “Image Deblurring with Blurred/Noisy Image Pairs”, Lu Yuan et al, SIGGRAPH07, Aug. 5-9, 2007, San Diego, Calif. are directed towards attempting to calculate a blur function in the main image using a second reference image before de-blurring the main image.
Other approaches, such as disclosed in US2006/0017837 have involved selecting information from two or more images, having varying exposure times, to reconstruct a target image where image information is selected from zones with high image details in SET images and from zones with low image details in longer exposure time images.